Tractor



FIG. 1 is a front view of a tractor showing my new design;

FIG. 2 is a rear view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a top view thereof;

FIG. 6 is an upper right front perspective view thereof; and,

FIG. 7 is an upper left rear perspective view thereof. 

CLAIM The ornamental design for a tractor, as shown and described. 